-ft fa? 




/fM 



*f 



014 421 124 8f 



Conservation Resources 



FOR OFFICIAL USE. 



REPORTS 



TO THE 



LOCAL GOVERNMENT BOARD 



ON 



PUBLIC HEALTH AND MEDICAL 

SUBJECTS. 



(NEW SERIES NO. 12.) 



Reports to the Local Government Board by 
Dr. G. S. Buchanan and Dr. S. B. Schryver, 
D.Sc, on the application of Formaldehyde 
to Meat. 

[Food Reports, No. 9.] 




LONDON: 

PRINTED FOR HIS MAJESTY'S STATIONERY OFFICE, 

By DARLING & SON, Ltd., 34-40, Bacon Street, E. 



And to be purchased, either directly or through auy Bookseller, from 

WYMAN and SONS, Ltd., Fetter Lane, E.C. ; or 

OLIVER & BOYD, Tweeddale Court, Edinburgh ; or 

E. PONSONBY, 116, Grafton Street, Dublin. 



1909. 
Price Twopence. 

Wonorranh 



n. OF D 



J> 



n 



*\ 



\ •^•\,^\> Food Reports, No. 9. 






Reports to the Local Government Board by 
Dr. G. S. Buchanan and Dr. S. B Schryver, 
D.Sc, on the Application of Formaldehyde 
to Meat. 



Arthur Newsholme, 

Medical Officer, 
July 28th, 1909. 



1.— Dr. BUCHANAN'S REPORT ON THE CIRCUM- 
STANCES OF THE INQUIRY. 

The use of formaldehyde for the preservation of meat has 
recently been brought to the notice of the Board in connection 
with — 

(a) Preparations of formaldehyde which are offered to meat 

purveyors and other dealers in perishable foods ; 
(Z») The use of meat safes fitted with arrangements by which 

the meat can be fumigated by formaldehyde ; 
(c) The use of formaldehyde in the fumigation of the holds of 
vessels in which chilled meat is brought to this country 
from South America and elsewhere. 



(a) Solutions of Formalin or Preparations containing Formaldehyde. 

The solutions here in question are made by suitable dilution 
either of commercial formalin (a solution of 40 per cent, of formal- 
dehyde in water) or of special preparations which contain formal- 
dehyde. When formalin or its preparations are offered to or used 
by dealers in perishable foods it may be presumed that the intention 
is frequently to employ the solution as a disinfectant or deodorant, 
i.e., to conceal incipient decomposition and to hide any smell of stale- 
ness or putrefaction : purposes for which formalin is well adapted. 
As an illustration may be mentioned a trade circular which lately 
came into my possession advertising a preservative which " arrested 
decay," was " non-poisonous and non-acid," and " of the greatest 
importance to poulterers, and all dealers in perishable articles of 
food." A testimonial from a provision merchant attached to the 
circular read as follows : — 

" It is only right that you should know that the treatment 

you gave my bacon and cheese with which were previously 

unfit for food are now saleable articles ; therefore, you can 
supply me with a quantity convenient for my use." 
This preservative, when examined by my colleague, Dr. G. W. 
Monier-Williams, was found to be a viscous substance containing 

(13588— 2L) Wt. 7335—682. 2000. 8/09. D & S. A 



common salt and glycerine, together with formaldehyde. There is 
no doubt that the virtues claimed for it would reside in the 
formaldehyde which it contains. 

Formalin solutions, or sprays, may also be applied to fresh meat 
at an early stage, in order to increase its keeping powers in hot 
weather. 



(b) Special safes for Formaldehyde Treatment. 

These safes are recommended for the treatment of fresh pro- 
visions for the purpose just referred to. They would no doubt also 
afford an efficient means of applying formaldehyde as a disinfectant 
and deodorant to tainted meat, if used with that object. The food- 
stuffs to be treated are placed on shelves or hung on hooks in a safe 
to one side of which, near the floor, a receptacle is attached. Into 
this receptacle are introduced pastilles, the essential constituent of 
which is polymerised formaldehyde (paraformaldehyde or trioxy- 
methylene). Paraformaldehyde depolymerises on heating and liberates 
the simple aldehyde in the form of vapour. A lamp is placed under- 
neath the receptacle containing the pastilles, and heating continues 
until the pastilles have completely volatilised. No appreciable residue 
is left. The food-stuffs are left in contact with the vapour in the 
closed safe for 20 minutes, or more, and the excess of formaldehyde 
is then removed by passing a current of air through the safe. The 
newer forms of apparatus are provided with a special appliance for 
effecting this ventilation. The safes are made in various sizes 
suitable to the requirements of restaurants or other eating-houses or 
for domestic use in hot climates. 

The apparatus has been applied to the formalisation of meat, 
eggs, milk, and other products. For the treatment of milk, a sieve 
is employed, which is placed in the roof of the apparatus. The milk 
is passed through the meshwork of the sieve, and in the finely 
divided state comes into contact with the formaldehyde vapour. It 
is then collected in a receptacle placed at the bottom of the safe. 
This form of the apparatus has also been used for formalising 
blood and gelatine used in the manufacture of blood sausages, 
brawn, &c. 



(c) Formalin treatment of Chilled Meat. 

This process has been devised for the purpose of preserving 
carcass meat during long periods of transit by sea. It has been 
found that simple chilling may fail to preserve the meat from the 
growth of moulds when the period of transit extends to several 
weeks, as is the case when beef is exported from South America to 
this country. The apparatus employed in this process consists of 
an air pump connected with a system of air conduits arranged 
around the chilling hold of the ship. The pump itself is situated in a 
small chamber adjoining the hold, and when the latter is closed the 
system forms a closed circuit through which, by suitable adjustment 



of the apparatus, either the atmosphere of the hold or formalin 
vapour may be circulated. The following is a brief account of the 
process to which the meat was submitted in the vessel from which 
were obtained the specimens of chilled meat on which Dr. Schryver 
has reported below : — 

The beef after being cut into quarters and dressed is first 
sterilised by means of formaldehyde vapour at the factory in 
Argentina. The quarters are then placed in sterilised cotton covers. 
Before the meat is brought on board, the chilling hold of the vessel 
is sterilised by circulating formaldehyde vapour through it. The 
vapour is obtained by volatilising formalin, 10 oz. of which are used 
to every 1,000 cubic feet of hold space. Volatilisation is carried 
out in a metal box which is fitted with a steam coil and com- 
municates with the circulating system by a valved opening. The 
vapour is then removed from the hold by a current of air. 

Af ter the hold has been fumigated and the vapour removed, the 
hatches are opened and the cargo of meat is placed on board, the 
quarters of beef being hung on hooks placed close together. When 
the loading is completed the hold is closed, and formalin vapour is 
once more circulated through it. At the same time the hold is 
brought to the chilling temperature (just below freezing point) 
which is maintained throughout the voyage. 

In the circulating apparatus already described there is an 
arrangement for drying the air during circulation. A box fitted 
with calcium chloride candles and leaden discs revolving in a bath 
of sulphuric acid is brought into the circuit by means of a valve. 
During the voyage, the atmosphere of the hold, with the formal- 
dehyde which it contains, is circulated over the drying reagents in 
a closed circuit for some hours every day. The calcium chloride 
and the sulphuric acid are renewed when necessary. In this way 
both the moisture and excess of aldehyde are removed. 

It will be seen that the object of the process is to combine chill- 
ing with sterilisation and desiccation, and by the employment of a 
system of closed circuit the attempt is made to guard the air from 
subsequent contamination after the formalisation has once taken 
place. 

From a sanitary point of view no objection can be taken to this 
process in so far as it forms a satisfactory and convenient method 
of disinfecting and sterilizing the hold in which the meat is placed 
during its vovage, and of keeping the meat in an atmosphere which 
besides being cold is dry and unfavourable to the growth of mould. 
Chilled beef is frequently carried from South America in satis- 
factory condition without the aid of formalin fumigation, but there 
are no doubt circumstances in which the treatment gives greater 
security, or extends the time during which the meat can be carried 
in a chilled condition. 

There are, however, substantial reasons for objecting to the 
presence of formaldehyde in food stuffs. It is a very powerful 
disinfectant; it may retard digestion even when present in the food in 
comparatively large dilution ; and it readily combines with the 
protein constituents of foods forming a compound which is less 
digestible than the original substance. These objections to formal- 
dehyde were considered by the Departmental Committee on Pre- 



servatives and Colouring Matters in Foods, 1901, which recommended 
that the use of formaldehyde or its preparations in foods or drinks 
be absolutely prohibited. 

In the case of chilled meat treated in the manner referred to, 
however, the process is a comparatively simple fumigation, the 
excess of vapour being readily removed after it has exerted its 
antiseptic function. It appears generally to be assumed that the 
penetration of the aldehyde into the meat in these circumstances 
is practically negligible, and that no more than a harmless, or 
even a desirable, surface disinfection is accomplished. The same 
belief seems to be held in the case of meat treated in formalin safes. 
A firm supplying the latter states that no disinfectant can be 
discovered in meat which has been treated by the process. 

This claim however, appeared open to some doubt in view of the 
readiness with which formaldehyde combines with the protein 
constituents of food stuffs and its ability to penetrate when it is 
used for other disinfecting purposes, and it appeared desirable 
experimentally to ascertain further facts on the subject. The work 
done for this purpose is shown in Dr. Schryver's report below. 
Part A contains an account of the considerations necessary in devising 
a suitable test for the determination of formaldehyde in meat, and 
gives the details of the method which Dr. Schryver has worked out 
in order to obtain approximate estimates of the quantities of form- 
aldehyde present in meat. Part B gives the results which Dr. 
Schryver obtained from the examination of a forequarter of chilled 
Argentine beef taken in London, with the assent of the importer, 
from the hold of a vessel in which formalin treatment had been 
employed. 

It will be seen that formaldehyde was recovered not only from 
various parts of the surface of the beef, but from parts below the 
surface, especially where the muscular tissue had not been covered 
by connective tissue or fat. Portions of the beef were also tested 
after ordinary cooking. Boiling and roasting appeared to reduce 
or even to remove the formaldehyde. Grilling, however, appeared 
merely to make the formaldehyde penetrate further into the substance 
of the meat. Cooked sausages made from the beef in question also 
contained formaldehyde. 

In view of the information now obtained, the meat importers 
and traders concerned should review their employment of the 
formalin treatment of chilled beef in the light of Dr. Schryver's 
results, and consider whether it may not be practicable, having 
regard to the end in view, to limit the use of formalin in the process 
to the adequate disinfection of the holds before the meat is intro- 
duced. 

The results have a special significance as regards meat which is 
treated in formalin safes. They indicate that articles like minced 
meat, fish, kidneys and other foods which expose a large surface in 
proportion to their weight cannot be subjected to this form of 
formaldehyde fumigation without absorbing relatively large 
quantities of this disinfectant. 

Gr. S. Buchanan. 



LI. Dr. SCHRYVER'S report on the presence 

AND DETECTION OF FORMALDEHYDE IN 
MEAT. 



A. The Detection and Estimation of Formaldehyde 

in Meat Foods. 

(1). Preliminary experiments on the sterilising efficiency of formalde- 
hyde ; the factors to be considered in devising a satisfactory 
method Jor its detection and estimation. 

In devising a method for the estimation and detection of 
formaldehyde in meat foods, the following possible reactions must 
be taken into account : — 

(a) It is possible that the formaldehyde may be entirely 

oxidised to carbon dioxide and water by means of the 
tissue oxydases* 

(b) It is possible that part of the formaldehyde may be poly- 

merised to paraformaldehyde. 

(c) Formaldehyde may enter into chemical combination with 

some of the constituents of the food stuffs. 

Each of these possible reactions requires some more detailed 
discussion. 

(«) It has been shown by Cervello and Pitini (Maly's Jahresber, 
1908, 37, 574, abstract from the Italian archives of pharmacology 
and therapeutics), and by Batelii and Stern (Biochem. Zeitsch., 
1908, 13, 44) that the tissue oxydases can destroy formaldehyde. 
If therefore the formaldehyde has been originally present in a tissue 
in such small quantities that it can be readily destroyed by the 
tissue ferments, it woidd be impossible to determine whether any 
given product had been formalised. Certain preliminary experi- 
ments confirm the statement that small quantities of formaldehyde 
are readily destroyed by tissue oxydases, but show moreover that 
unless these quantities have been exceeded, formaldehyde treatment 
is quite ineffective for sterilisation. 

The above remarks are illustrated by the two following experi- 
ments : — 

10 cc. of formaldehyde solution of the following concentrations, 
5:200,000, 5:100,000, 5:50,000, 5:10,000, 5:7,500, 5:5,000, 
5 : 2,500 were added to 40 cc. milk. Two sets of experiments were 
carried out with each concentration, the milk in one set beiug 
unheated, and in the other kept in a boiling water-bath for five 
minutes (a proceeding which would destroy the oxydases of the 
milk) and then cooled before the addition of the formaldehyde. 
The milk contained the formaldehyde, therefore, in the concentra- 
tions 1 : 200,000, 1 : 100,000, 1 : 50,000, 1 : 10,000, 1 : 7,500, 
1 : 5,000, 1 : 2,500. All samples were incubated at 37*5° C, and at 
various intervals 5 cc. were removed from each sample and tested 
for formaldehyde by warming with 3 cc. concentrated hydrochloric 
acid and one drop of dilute ferric chloride solution. After 20 hours 
formaldehyde could not be detected in the unboiled samples contain- 
ing originally less than 1 part in i 0,000 ; it could be detected, 



6 • 

however, in all the boiled samples, giving however only a very faint 
reaction with the sample that contained 1 part in 200,000. It was 
quite distinct in all the others. Similar results were observed after 
three days' incubation. After five days the formaldehyde could not 
be detected in the boiled sample containing originally 1 part in 
50,000. Tests were also made after intervals of 7 and 11 days, 
and all indicated that the formaldehyde disappeared considerably 
more rapidly from the unboiled than from the boiled samples. No 
attempts were made to keep the samples sterile during the period of 
incubation ; nor were attempts made to detect combined formalde- 
hyde or paraformaldehyde. The experiments were carried out 
before the reactions applicable in these cases had been elaborated. 
They indicate clearly, however, the fermentative destruction of the 
aldehyde by fresh milk, in which the enzyme had not been destroyed 
by heat. 

The second series of experiments were carried out with meat : — 
Samples of 20 grams of meat were ground up with sand and 
mixed in each case with 5 cc. of formaldehyde solution of the 
following concentrations :— (i) 5 : 200,000 ; (ii) 5 : 100,000 ; (iii) 
5 : 50,000; (iv) 5 : 10,000; (v) 5 : 7,500; (vi) 5 : 5,000; (vii) 
5 : 2,500 ; (viii) 5 : 1,000 ; (ix) 5 : 500. 

The meat samples contained therefore one-fifth of the above 
quantities calculated on their total weights. They were placed in 
corked test tubes and allowed to stand for five days at ordinary 
laboratory temperature. After this period, all the samples which 
contained originally less than 1 part of formaldehyde in 5,000 had 
a distinctly putrid smell, whilst the sample which had contained 
1 part in 2,500 was covered with moulds. The samples with larger 
quantities had lost their pinkish colour, and were dirty yellow. 
They were then heated with 20 cc. water and the coagulum 
separated from the fluid by filtration through calico. Formal- 
dehyde was tested for in both the filtrate and in the coagulum by 
the method finally adopted, and to be described in detail below. 
It could be distinctly detected in the filtrate from the sample 
containing originally 1 part in 2,500 and in those containing larger 
quantities. It could be detected in the coagulum only of the 
samples which had contained 1 part in 5,000 and 1 part in 7,000. 
It was entirely absent both in coagulum and filtrate in the samples 
which had contained less than these quantities. 

The course of putrefactive change was investigated in some detail 
by determining the rate of putrefaction of meat in the presence of 
varying strengths of formaldehyde solutions by measuring the 
changes of electrical conductivity of the solutions after different 
intervals of incubation (compare Schryver and Lessing, Journ. Soc. 
Chem. Ind., Jan. 1909), and substantially the same results as the 
above were obtained. 

The result of these experiments indicates that formaldehyde is 
entirely destroyed by the tissue when present in small quantities. 
It is ineffective as a preservative unless present in quantities 
exceeding these small amounts. The experiments indicate a priori 
that where formaldehyde has acted efficiently as a preservative, it 
should be subsequently detectable provided that an efficient method 
is available. 



(b) When formaldehyde solution is distilled a distillate is obtained 
which contains less aldehyde than the original solution. This is 
due to the fact that it polymerises during heating into a non-volatile 
polymer which remains behind in the residue after distillation. The 
conditions under which this polymerisation takes pjace have been 
investigated in detail by Auerbach and Barschall (Arbeiten 
aus dem Kaiserlichen Gresundheitsamt, 1905, 22, 606, and 1908, 27, 
183). 

It is not possible therefore to estimate formaldehyde present in 
a sample by submitting it to steam distillation and determining the 
amount of the aldehyde in the distillate, Furthermore, in the case 
of chilled meat treated with formaldehyde it is possible that 
some of the formaldehyde undergoes polymerisation whilst the 
meat is in the chilling chambers. A satisfactory method for 
estimating the degree of f ormalisation should be applicable, therefore, 
not only to the detection and estimation of the free form but also of 
its polymer. 

(c) Meat and other food products contain proteins and amino- 
acids, which can react with formaldehyde with the formation of 
methylene-imino derivatives. This reaction has formed the subject 
of exhaustive investigation by SchifT and Sorensen, who have shown 
that it is a reversible one and only proceeds to completion in the 
presence of a large excess of formaldehyde. The reaction may be 
represented in the case of one of the simplest of the amino deri- 
vatives, viz., glycine, by the following equation — 

(NH 3 )CH 2 .COOH + HCHO Z CH 2 : N.CH 2 .COOH + H 2 0. 

It has been employed recently by Sorensen in investigation of 
digestion products. Amino-acids and similar substances, which 
owing to the presence of both basic and acidic groups have an ampho- 
teric reaction, become strongly acid after treatment with formalde- 
hyde, and the number of amino groups which enter into combination 
can be consequently determined by titration with alkali. Conversely 
it is possible by titration to estimate the amount of formaldehyde 
which can enter into combination with any product. Meat products 
contain relatively large quantities of substances which are capable 
of entering into chemical combination with the aldehyde, as the 
following experiments show : — 

20 grams of meat were ground up with sand, and heated with 
50 cc. of water till the proteins were coagulated. The coagulum 
was separated from the liquid by pressure, and the filtrate and 
washings made up to the volume of 100 cc. These were neutralised 

N 
with -r barium hydroxide solution ; 50 cc. of neutralised 40 per cent. 

formaldehyde solution were then added, Owing to combination 

with amino-groups, the mixture for reasons above stated became 

N 
strongly acid and required 6*05 cc. of -~ barium hydroxide to 

neutralise. From this result it was calculated that the extractives 
alone from 100 grams of meat were capable of combining with 
363*3 milligrams of formaldehyde. A second experiment indicated 
that the extractives from 100 grams would combine with 366 milli- 



grams of the aldehyde. The reaction, as already mentioned, will 
not proceed to full completion except in presence of excess of 
aldehyde owing to the reversibility. 

In addition to these reversible compounds, formaldehyde can 
combine with substances belonging to the class of proteins to form 
relatively stable insoluble products, from which formaldehyde can 
be eliminated only by prolonged heating with water. In another 
connection I propose to describe the preparation of such compounds 
and the conditions under which they can be obtained. 

The results of these preliminary observations may be summarised 
as follows : — 

(i) Relatively large quantities of formaldehyde would be 
necessary to protect meat foods for any considerable 
period against decomposition, 
(ii) Any effective method for estimating the formaldehyde in 
such products must be applicable not only to the 
estimation of free aldehyde, but also of the polymerised 
product and of the aldehyde which has entered into 
combination with the food constituents. 

(2) Method of Estimation of Formaldehyde. 

Weak formaldehyde solutions were made by diluting a 5 per cent, 
solution which had been standardised by several methods. Some of 
those described in the literature were found to be quite satisfactory 
whereas others contain various sources of error. 

The following were found to give satisfactory results : — 
Legler's method (Klar's modification, Pharmazeutische Zeitung, 1895, 438). 
Romijn's cyanide method. 
Romijiis iodometric method, as modified by Fresenius and Griinhut and 

Bernard Smith (Journ. Amer. Chem. Soc, 1903, 25, 1028). 
Schlfs method (Male's modification, Zeitsch. f. Untersuchung der 
Nahrungs u. Genussmittel, 1906, 11, 485). 

Less satisfactory results were obtained by : — 
Griitzner 's method (Arch. d. Pharm. 234, 64). 

Blank and Finkenbeiner 's method (Schorl's modification, Zeitsch. f. Unter- 
suchung der Nahrungs u. Genussmittel, 1908, 15, 240) ; and 
Vanind's method (Zeitsch. f. analytische Chemie, 40, 720). 

In these latter methods slight variations of conditions of experi- 
ment, such as temperature, time of heating, &c, caused considerable 
variations in the results. The method most frequently employed 
was Romijn's iodometric method (see Sutton's volumetric analysis). 

Estimation of Small Quantities of Formaldehyde. 

A large number of colorimetric reactions, which are applicable 
to detection of very small quantities of formaldehyde, are 
described in the literature, and have been investigated, but none 
of them were found entirely satisfactory for the purposes of quanti- 
tative estimation in the case of meat. A violet colour is obtained 
when formaldehyde is warmed with proteins and concentrated 
hydrochloric acid in the presence of oxidising agents, and this well 
known reaction in various forms has been applied to the detection 
and estimation of formaldehyde in milk. It is, however, quite 
unsuited to the detection of the aldehyde in meat, owing to the fact 



that meat gives a violet colour on warming with hydrochloric acid 
in the absence of the aldehyde, due to the formation of hamiato- 
porphyrin from the haemoglobin. 

After prolonged trials of many reagents the following reaction 
was discovered, by means of which small quantities of formaldehyde 
could be detected and colorimetrically estimated : — 

To 10 cc. of solution containing the aldehyde are added 2 cc. of a freshly 
made and filtered 1 per cent, solution of phenylhydrazine hydro- 
chloride. To this is added 1 cc. of a 5 per cent, fresh potassium 
ferricyanide solution. To the mixture, 4 cc. of concentrated 
hydrochloric acid are then added. In the presence of 
formaldehyde, a brilliant juchsine-like colour is developed, which 
readies its full intensity after a few minutes standing and keeps 
luithout mai'ked deterioration for several hours.* 

The addition of ferricyanide oxidises the formaldehyde 
condensation product to a substance which is a weak base, which 
forms a scarlet hydrochloride. This, on dilution, undergoes 
hydrolvtic dissociation, yielding a base which can be extracted by 
ether to form a yellow solution. If this latter be shaken with 
concentrated hydrochloric acid, the base passes back into aqueous 
solution m the form of the scarlet hydrochloride. 

By this reaction, formaldehyde when present in the concentration 
of only one part in one million can be readily detected. It is 
quantitatively best applied when the concentration of aldehyde is 
not more than one part in 50,000. When applied to greater 
concentrations, it is advisable to dilute the original solution before 
treating with the phenylhydrazine and ferricyanide reagents. From 
two standard solutions containing respectively one part in 10,000 
and one part in 100,000, it is possible to make a series of dilutions, 
from one part in a million upwards, to serve as a colour scale when 
the reaction is quantitatively applied. 

Application of the above reaction to detection and estimation of 
polymerised formaldehyde or formaldehyde which has entered into 
combination with other substances. 

As already mentioned, formaldehyde readily polymerises or 
enters into combination with amino derivatives, proteins, &c, with 
the formation of methylene-imino derivatives, which can be readily 
hydrolysed by cold water {see above p. 7). With ammonia it 
forms a somewhat more stable derivative, and with Witte's 
peptone, under certain conditions, an insoluble product, from which 
formaldehyde is only eliminated with some difficulty.t 

* Rimini described a reaction for formaldehyde in which the solution is 
treated with phenylhydrazine hydrochloride, ferric chloride and hydrochloric 
acid. The same pigmented product as is described in the above reaction is 
obtained. Rimini's reaction is inapplicable to quantitative work. If ferric 
chloride be added in too small a quantity, the pigment is not fully developed. 
If on the other hand it be added in too large a quantity, the colour is rapidly 
destroyed. Compare also Arnold and Mentzel. Zeitsch. f. Untersuchung der 
Nahrungs u. Genussmittel, 1902, 5. 354 and 687. 

t This will be described in a subsequent publication. 

13588 B 



10 

By modification of the above reaction, formaldehyde can be 
detected in all such combinations. If the mixture containing such 
product be warmed after addition of phenylhydrazine, the aldehyde 
after scission combines immediately with phenylhydrazine to form 
a stable condensation product. This reaction, being irreversible, 
proceeds to completion. On the addition of the ferricyanide and 
hydrochloric acid, the colour is developed in its full brilliancy. 
Thus, for example, if 10 cc. of solution (one in 1,000) of hexa- 
methylenetetramine (urotropine), the condensation product of 
ammonia and formaldehyde, be treated in the cold with 2 cc. of 
1 per cent, phenylhydrazine hydrochloride and 1 cc. of 5 per cent, 
potassium ferricyanide and 4 cc. concentrated hydrochloric acid, a 
colour will develop very slowly. The hexamethylenetetramine is 
slowly hydrolysed with the formation of formaldehyde, which then 
gives the characteristic reaction. If, however, the solution of 
hexamethylenetetramine be boiled after the addition of the 
phenylhydrazine and then cooled, and the other reagents be then 
added, the full colour due to the formaldehyde will be almost 
immediately developed. 

By the same modification of the reaction (viz., heating after 
addition of phenylhydrazine), formaldehyde can be detected even 
when present in its polymerised form. 

Detection and Estimation of Formaldehyde in Meat. 

Meat is heated for five minutes in a boiling water bath with 
water to every 10 cc. of which have been added 2 cc. of a 1 percent, 
phenylhydrazine hydrochloride solution. 10 grams of meat pre- 
viously minced are generally employed for each experiment, but the 
quantity of liquid is varied according to the amount of formaldehyde 
present. In most cases where the amount of formaldehyde is 1 part 
in 50,000 or less, 10 cc. of water and 2 cc. of phenylhydrazine solution 
are employed. Where the concentrations are higher, larger quantities 
of liquid must be used. Thus, where the concentration of the 
aldehyde reaches in the meat 1 part in 5,000, IX) grams of meat are 
heated with 100 cc. of water and 20 cc. of 1 per cent, phenyl- 
hydrazine hydrochloride solution, After heating, the liquid is 
cooled and filtered from the coagulum through a loose plug of cotton 
wool. To 12 cc. of the filtrate are added 1 cc. of 5 per cent, 
potassium ferricyanide solution and 4 cc. of concentrated hydro- 
chloric acid for each 12 cc. of water and phenylhydrazine reagent 
employed in the test. By comparison of the colour with standards 
made from the standard formaldehyde solutions, the amount of 
formaldehyde in any given meat sample can be ascertained. 

B. The Examination of Chilled Beef treated by a 

Formalin Process. 

For the purposes of determining the amount of formaldehyde 
remaining in meat after formalisation, and its distribution and 
penetration, part of a forequarter of beef was selected from the 
chilling hold of a vessel which had arrived in London from the 
Argentine Kepublic. The meat had been treated by a formalde- 



11 

hyde fumigation process, and was seen by me in the chilling chamber 
on April 10th, 1909, after it had been 53 days on board 
(temp. 29'5° F.). In this instance the meat had undergone a second 
formalisation on board on March 28th, when off Teneriffe. The 
forequarter chosen for examination was taken from a part of the 
chamber near the inlet holes, and was kept for four days in a cool 
place before being submitted to examination in the laboratory. 

Sections cut parallel to the surface were taken from various parts 
of the meat and the penetration of the aldehyde was ascertained 
in cases where different kinds of surface, such as fat, muscular 
tissue, &c, had been directly exposed to the vapour. 

The following analyses were made : — 

Superficial Fat showed distinct quantities of formaldehyde. 

Muscular Tissue lying beneath a thin layer of Fatty Connective 
Tissue. — Sections parallel to the surface were taken from the neck, 
under a thin layer of fatty connective tissue. These were approxi- 
mately 20 millimetres thick (over j inch), and were divided into 
four approximately equal parallel sections each about 5 mm. 
thick. The three outer sections contained formaldehyde in the 
quantity of about 1 in 30,000, whereas the fourth section contained 
only a trace. 

Immediately under the 20 mm. section was an aponeurosis. A 
section containing this (mixed connective and muscular tissue) 
showed a small quantity of formaldehyde (about 1 in 100,000). 
The formaldehyde hardly penetrated below the aponeurosis. 

The total penetration in the neck, therefore, under a thin layer 
of connective tissue, was a little more than 20 mm. 

Muscular Tissue under a substantial layer of Superficial Fat. — 
The sections in this case were also taken from the shoulder under 
a layer of fat 7 mm. thick. The first section of underlying muscular 
tissue (5 mm. thick) contained formaldehyde in a quantity of about 
1 in 35,000. The second section (5 mm. thick) contained small 
quantities (less than 1 in 100,000). Below this section formal- 
dehyde was absent. 

Muscular Tissue, the Surface of which is unprotected by Fat. — 
For examining penetration when muscular tissue is exposed, 
analyses were made of samples taken from the shoulder to a 
depth of 10 mm., at which depth an aponeurosis was reached. 
The first section (5 mm. thick) contained formaldehyde to the 
extent of one part in 3,500. The second section (5 mm. thick) 
contained formaldehyde to the extent of a little more than 1 in 
10,000. In sections taken below the aponeurosis do formaldehyde 
could be detected. 

Superficially exposed muscle is, therefore, more largely contami- 
nated than other parts. The penetration is, however, somewhat 
limited, as the heavy formalisation of the outer surfaces tends to 
render them impervious to the aldehyde vapour. 

Attempts were made to detect formaldehyde in representative 
portions of meat cut from different parts of the forequarter. 
Sections were cut through the shin, the neck, and the shoulder. 
Each was finely minced and examined for formaldehyde. In the 



12 

shin, which contained a large amount of exposed superficial 
muscular tissue, formaldehyde could be readly detected. It could 
also be found in the other sections, although the reaction was only 
faint in the section obtained from the neck. 

Effect of Cooking. 

The effect of cooking was also investigated. 

Grilling. — In grilled steaks, taken from superficial parts of the 
shoulder and neck, formaldehyde was detected in but slightly 
diminished quantities. The effect of grilling had apparently been 
to make the aldehyde penetrate further into the interior of the 
meat. 

Boiling. — A part of the shin, with a large amount of exposed 
muscular surface, was boiled. Formaldehyde was detected after 
boiling, but in greatly diminished quantities (1 in 30,000 in outer 
section, i.e., about one-tenth of the original quantity). 

Roasting. — In the roasted ribs, no formaldehyde could be detected 
after cooking. 

Cooked sausages. — Sausages were made from exposed muscular 
parts of the joint. Formaldehyde could be detected in these 
sausages after cooking in the ordinary way. 

General Results. 

The results indicate that, in the case under consideration, form- 
aldehyde was not readily removed from meat even when the latter 
had been kept for prolonged periods after formalisation ; that where 
muscular surface was exposed to the vapour, the contamination was 
relatively large (1 in 3,500); and that a common depth of penetration 
into muscular tissue was 20 mm. under a thin superficial layer of 
connective tissue. 

S. B. SCHRYVER. 

University College, 
London. 



\ 



LIBRARY OF CONGRESS 




LIBRARY OF CONGRESS 



014 421 124 8 * 



